Conventional engines are roughly divided into three types: a reciprocating engine in which power is obtained by reciprocating motion of a piston caused by combustion of fuel; a jet engine in which thrust force is obtained by combusting a mixture of fuel and air compressed by using a compressor, and in which a turbine providing rotational power to the compressor is rotated by the combustion gas generated by the combustion; and a scram engine in which thrust force is obtained by supersonic combustion performed by spraying fuel into intake air compressed by ram pressure (see, for example, Patent Literature 1).